Approximations for Large-Molecule Calculations

Abstract

The papers in this section deal with the actual computational methods used in studies of the electronic structures of large molecules and localized states in solids. Such studies differ from those applicable to small molecules through the necessity of choosing methods which do not outstrip our computing capacities, and differ from conventional infinite-crystal studies through a lack of exploitable translational symmetry. The regime under consideration is thereby characterized by a maximum in difficulty of precise calculation, but this difficulty is to some extent compensated by the fact that relatively crude results can often be highly useful.